Chai Discovery Signs AI Drug-Development Deals With Pfizer and Eli Lilly, Plans $400M Raise at $3.4B Valuation

Chai Discovery announced a drug-development partnership with Pfizer after signing a similar agreement with Eli Lilly in January 2026. 4 billion valuation. Nearly 20 pharmaceutical companies contacted Chai Discovery after it released an antibody design model in June 2025.

The startup is currently in discussions with more than 15 additional drugmakers and expects to sign more deals this year. It offers its earlier Chai-1 protein-folding model free of charge so potential customers can test the technology. The Chai-3 model doubles the success rate of its predecessor and produces antibodies that bind 100 times more tightly to their targets.

In roughly half of cases, molecules generated by Chai-3 bind as tightly as approved drugs. Chai-2 had spun out antibody designs from scratch 16 percent of the time. Pfizer had $63 billion in revenue in 2025.

Eli Lilly has a $1 trillion market capitalization. A typical drug costs well over $1 billion to develop and takes more than 10 years. Chai Discovery has raised more than $225 million from investors including OpenAI, General Catalyst, Menlo Ventures and Oak HC/FT.

6 billion in 2024. 5 billion has been committed, according to PitchBook data. 1 billion in May 2026.

Cofounder and president Jack Dent said the June 2025 model release prompted immediate outreach. “It was like we dropped a bomb on the field,” he said. ” Cofounder and chief executive Josh Meier, 30, said the company aims to improve medicine quality.

“We want to raise the bar of medicines that are created,” he said. ” Dent, 29, said earlier AI models had limited practical value. “The models were smoke and mirrors for a long time,” he said. ” Board member Mikael Dolsten, who retired from Pfizer as president of worldwide research and development, said the decision to license technology rather than develop proprietary drugs helped attract partners.